This SBIR Phase II proposal is a plan to further develop a novel therapeutic approach that will save the lives of patients with sepsis. Despite the increased understanding of the complex pathophysiology of sepsis, severe sepsis still results in significant morbidity and mortality. As such, there is an urgent unmet medical need for an effective novel therapy for septic patients. The global market potential for sepsis treatment is estimated at over $30 billion annually. Thus, successful development of a new anti-sepsis therapy will not only have a positive impact on health care, but also will have significant commercial benefits. A balanced inflammatory response is an essential element of a successful host defense after injury. However, excessive production of proinflammatory cytokines may cause further tissue injury. Macrophages/Kupffer cells play important roles in producing proinflammatory cytokines in sepsis. The nervous system reflexively regulates the inflammatory response in real time. We have demonstrated that the release of the sympathetic neurotransmitter, norepinephrine (NE), from the gut is increased in sepsis, and that NE potentiates endotoxin-induced TNF-( upregulation via the A subtype of (2-adrenoceptors (i.e., (2A-AR) expressed on the surface of Kupffer cells. Pre-treatment with a specific (2A-AR antagonist, 2-[(4,5-dihydro-1H-imidazol-2-yl) methyl]-2,3-dihydro-1-methyl-1H-isoindole maleate (BRL- 44408 maleate), downregulates TNF-(, attenuates tissue injury, and improves survival in a rat model of polymicrobial sepsis induced by cecal ligation and puncture (CLP). However, it remained unknown whether the delayed administration of BRL-44408 maleate (which is more clinically relevant) reduces sepsis-induced mortality as well. Accordingly, the primary objective of our completed Phase I project was to determine the effect of delayed administration of BRL-44408 maleate on sepsis-induced inflammation, organ injury, and mortality. We have clearly shown that administration of BRL-44408 maleate at 5 h after CLP (i.e., at the early stage of sepsis) is protective in experimental animals. These results have established the technical merit and feasibility of the proposed Phase II project. We therefore continue to hypothesize that the administration of the small molecule drug candidate BRL-44408 maleate in established sepsis attenuates tissue injury and improves survival. In this Phase II proposal, we will perform detailed toxicological evaluation and pharmacokinetic characterization, and determine the optimal protective dose(s) and time- course of BRL-44408 maleate in sepsis in the rat. In order to advance the technology to clinical trials, the efficacy of BRL-44408 maleate will be tested in a rabbit model of sepsis. These proposed studies should provide important preclinical data that will help us filing an IND application to the FDA to initiate clinical trials in order to obtain commercial utilization of BRL-44408 maleate as a safe and effective therapy for sepsis.